anemia: A condition caused by a lack of red blood cells, the cells that transport oxygen to the body’s tissues.

antibodies: Proteins made by your body that fight off foreign substances.

antigen: A foreign substance, such as a bacteria, virus, or tissue, that does not come from your body.

apheresis: A process in which whole blood is drawn from a donor, the stem cells are then harvested, and the other blood products are returned to the donor.

autologous: Stem cell transplantation using your own stem cells.

bone marrow: The spongy part of some bones, where blood cells develop from immature marrow cells called stem cells.

bone marrow transplant (BMT): A transplant containing all three types of blood cells that develop in the bone marrow: red cells, white cells, and platelets. (Stem cell transplants only use the immature stem cells from the circulating blood.)

human leukocyte antigens (HLA): Proteins found on the surface of white blood cells and tissues. A tissue-typing test shows how many HLA matches the recipient has in common with a donor.

immune system: A network of cells, tissues, and organs that protects your body from disease and infection.

indwelling catheter (central line): A tube surgically placed in your chest near your neck through which to give chemotherapy and receive your stem cell infusion. It may also be used to draw blood. This type of catheter is also known as a “port.”

infusion: Delivery ofliquid medicine or treatment through a vein.

matched unrelated donor (MUD): A donor who is not a blood relative, but who has a complete HLA match to the patient. These donors are often found through bone marrow registries